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Saving Energy for Fruit Production

Posted: July 22, 2011

Energy-efficient practices on the farm bring to mind fancy new equipment like solar panels, wind turbines, and biofuels. But you don’t have to jump head-first into buying the latest technology. With just a few simple changes to your operation, you can start to see real savings at the pump and on your electricity bill.

Storing your irrigation pump and filtration system in a protected area translates to smart energy savings.

Dr. Katie Ellis, Penn State Specialty Crops Extension Educator

Saving Fuel

The biggest
energy drain on in-field tree fruit operations is fuel use for tractors, trucks
and other farm equipment. Mowing,
spraying, checking traps and moving bins and harvest crews around orchards can
consume a lot of fuel. More precise pest
management methods can help reduce fuel use, as can a move to higher density
plantings. But how can you save fuel
even more? Alex Leslie, a graduate of
Penn State’s Agricultural and Biological Engineering program, developed a fuel
use calculator for tree fruit orchard blocks.

To calculate
estimated fuel use for specific blocks, you enter several variables like block
size, tree row spacing, planting density, current diesel price and
tractor/sprayer type. The program
computes the number of passes and turns required, and the resulting fuel cost
based on the equipment used. By
manipulating the variables and trying different combinations, you can determine
the most efficient use of fuel in your operation. For a copy of the calculator, please contact
Katie Ellis at kag298@psu.edu or 717-334-6271.

You can also
save fuel (and time) by ensuring that your farm equipment is
well-maintained. Quick fixes and neglect
will only cause headaches later on – and energy efficiency will suffer,
too. Also, be strategic about tractor
and truck usage. Proper planning will
ensure that you save time and money in the long run.

Irrigation

The second
biggest use of in-field energy is in crop irrigation, and it is possible to reduce fuel and/or
electricity through adjustments to your irrigation system. There are three areas to investigate in order
to cut irrigation costs: 1) soil
studies, 2) proper water usage, and 3) pump maintenance. First, studying your soil structure will help
you understand its properties – well-aggregated soils let water enter easily
and retain water well. Planning your plantings
based on soil type will help maximize water use efficiency. Increasing organic matter also helps with the
soil’s water-holding capacity.

Proper water
usage involves matching irrigation to the crop’s needs. This depends on many factors such as
temperature, relative humidity, wind speed and crop coefficients like tree age,
height, cultivar and crop load. In
short, you must determine how much water was taken from the soil and then
replace it through irrigation. This is
most easily accomplished through automated soil monitoring systems, but you can
take measurements manually and then schedule irrigation needs accordingly.

Finally, energy
waste can occur from a lack of pump maintenance. On average, irrigation systems use 40% more
fuel if they are improperly sized, adjusted and/or maintained. Also, about 25% of electricity is wasted from
poor pump and motor efficiency. Most
energy waste occurs at the pump itself: this
occurs from wear, improperly designed fittings or lack of maintenance. Keeping the pump clean, lubricating when
necessary, replacing worn gaskets and protection from the elements all go a
long way in maximizing the energy efficiency of your irrigation system. When using an electric motor, be sure to use
a shade to cool the thermal breakers.
Also, drip irrigation can lead to special irrigation problems. Since lines are easily clogged by soil, algae
or particulate matter from chemical treatments, be sure to check filters,
pressure and flush the system periodically.

To give
yourself a rough cost estimate of your irrigation system, try out the
irrigation estimator tool offered by USDA-NRCS: http://ipat.sc.egov.usda.gov/.
You’ll need to enter a bit of information about your operation, and the
calculator will tell you approximately how much money you’ll save per season by
adding a flow meter, scheduling your irrigation and maintaining/upgrading your
system.

Refrigeration

If your farm
has on-site cold storage, you already know how energy usage affects
profit. Refrigeration can be a huge
energy hog, but there are ways to make it more efficient. First, try to minimize warm air leakage into
the refrigerated space by adding insulation, door flaps and reducing movement
in and out of the storage. Doubling
insulation can reduce heat loss by 50%, and remember that polyurethane
insulation loses its insulating value over time. Forklift traffic often degrades insulation
near doorways, so repairs may be in order.

Routine
maintenance, like cleaning fans and coils, can help maximize system
efficiency. Since lights produce heat,
turn them off (and other heat sources) whenever possible, or install time or
motion sensors. If your operation has a
use for hot water, set up the system to recover heat from the hot
refrigerant. Also, turn up the
thermostat or shut off the storage when not in use. This sounds obvious, but we’ve all seen it –
a storage with half a bin of apples and the refrigeration on full-blast.

If the storage
is really inefficient, it may be time
to replace the refrigeration system with a higher efficiency unit. Newer equipment utilizes more energy
efficient scroll compressors. Newer
units also employ more efficient controls, like anti-sweat heater and hot gas
defrost systems. If you’re not familiar
with the latest systems, you may benefit from an energy audit; this can help
you calculate the payback time and potential energy savings.

Energy Audits

A third-party energy assessment
can help you identify ways to save energy throughout your operation. A fresh set of eyes can sometimes spot
inefficiencies, from simple fixes like switching out old light bulbs to finding
major energy hogs. A special audit
opportunity is offered through the “Pennsylvania Farm Energy Audits Program,” a
partnership between USDA Rural Development, Capital Resource Conservation and
Development Council, Center for Dairy Excellence and Penn State Cooperative
Extension.

USDA will offset the cost by
paying 75% of the energy audit, leaving only 25% of the cost to the farmer.
The audits are carried out by Penn State agricultural energy specialists
or specially trained private consultants, depending on the location of the farm
and availability of personnel. Since an
energy audit is the required first step for many funding programs, this offers
growers an excellent opportunity to assess their on-farm efficiency. For more information about the application
process, visit http://extension.psu.edu/energy/farmers-landowners/pa-farm-energy-audits-program.